Local Area Network Management

Transcription

1 Technology Guidelines for School Coputer-based Technologies Local Area Network Manageent Local Area Network Manageent Introduction This docuent discusses the tasks associated with anageent of Local Area Networks (LANs). All LANs require regular adinistration and anageent in order to function efficiently and effectively. A Network Adinistrator is required to perfor a range of duties in order to achieve this efficiency and effectiveness. These include aintaining syste security, ipleenting backup strategies, installing software, upgrading software, anaging data storage and ensuring provision of virus protection. Training Adinistrators In soe cases, schools ay choose to retrain existing staff to take on the role of Network Adinistrator. Other schools ay choose to outsource this service. Schools ay also wish to develop their own support networks within local groups and via e-ail through the Internet to share ideas and experiences regarding coputer network adinistration. Your District Technology Adviser can also offer advice in this area. If the school intends to take on the network adinistration tasks itself, an appropriate training course for the school Network Adinistrator is desirable. Specific Network Adinistrator training courses are available for various network platfors (Novell Netware, Windows NT Advanced Server, Apple Macintosh Workgroup Server etc). These are norally provided by coercial training centres, and in soe cases, accreditation is available. Soe TAFE colleges also offer siilar training courses however these are norally spread out over a longer period of tie. The school ay wish to consider using funding for the Coputer Coordinator resource as a way to support anageent of the coputer network in this way. The use of a second or third person to shadow the ain network adinistrator or the sharing of adinistration tasks aong two or three staff will reduce the dependency on one person in the school. Situations where only one adinistrator is anaging the whole network should be avoided. In the case where this person leaves the school or is not available for a period of tie, it would ean the entire network adinistration knowledge in the school would also be unavailable. Inforation Technology Bureau MLANS304.doc 1 Educational Technologies Unit

2 Technology Guidelines for School Coputer-based Technologies Local Area Network Manageent The alternative is outsourcing soe or all adinistration tasks to an external service provider. Many coercial network adinistration providers offer a dial-up adinistration service whereby the provider accesses the syste via a phone link to perfor any adinistrative tasks at a uch cheaper rate than incurred through site visits. This ay be particularly useful for schools in country areas where access to technology professionals ay be costly due to distances involved. Soe tasks such as software installation would ost likely have to occur on-site. Regardless of whether the school chooses to perfor its own adinistration or have it outsourced, it is highly recoended that coprehensive details of the school s coputer network such as layout, configurations and software licences be produced and updated as necessary. Methods for autoating coon adinistration functions such as printer queue aintenance, backup processes and user setup should also be developed and docuented for future referral. Master passwords for all parts of the syste should be written in a book and stored in the school safe. It is also helpful to produce a list of work practices or rules for the use of coputers and affix the near each workstation. This will help reinforce the school s policy with regard to the use of coputers and the local area network. Regular Maintenance Tasks Aside fro syste backup and software installation which are discussed in separate sections, soe of the regular aintenance tasks include: workstation network client set-up; network interface card testing/installation/replaceent; cable testing; cable patching; purging of deleted files; new user setup; user password aintenance; user support; printer / peripheral configuration and aintenance; general troubleshooting. These tasks are vital to the continued operation of the school s coputer network. Inforation Technology Bureau MLANS304.doc 2 Educational Technologies Unit

3 Technology Guidelines for School Coputer-based Technologies Local Area Network Manageent Backup, Recovery and Contingency Planning When it reaches the stage that the school is utilising either a centralised or distributed application and data syste, it is vital that syste downtie be avoided or at least iniised. If any of the following coponents of the network fail, all (or at least soe) of the syste will be unavailable for use: 1 AC Power (blackout / surge / spike / brownout); 2 File server(s); hard disk / hard disk controller; power supply; otherboard; network interface card. 3 Hubs (particularly those connected to the servers); 4 Cable backbone. The school s contingency (or disaster recovery) plan should provide solutions to be able to recover (quickly) fro any of the coponent failures entioned above. As exaples, the following solutions are available: Uninterruptible Power Supply (UPS) for server(s) and hubs; tape backup syste to regularly backup server hard disks; hard disk irroring; server irroring; duplication of cable backbone; avoiding single points of failure. As an absolute iniu, a UPS for the server(s) with server shutdown capability and a reliable tape backup strategy ust be incorporated in the contingency plan. File server: one of the achines in a local network that serves as a data storage centre i.e. a place where all the shared data files used throughout the network are stored. otherboard: this is where the electronic circuits are located for processing and storing data. hub: hardware or software device that contains ultiple independent but connected odules of network and Internetwork equipent. Hubs can be active (where they repeat signals through the) or passive (where they do not repeat, but erely split, signals through the). cable backbone: this type of cabling links together the various segents of a LAN e.g. potentially linking ultiple buildings or floors. uninterruptible power supply: a UPS is a basic unit for ensuring an even flow of power to a fileserver. Brown/black outs, power surges / spikes and power cuts can all be accoodated e.g. when a power cut occurs, the UPS can broadcast a prerecorded essage over the network warning users to save their work and then turn off (down) the file server correctly. irroring: this is the process of aking a duplicate backup copy. Inforation Technology Bureau MLANS304.doc 3 Educational Technologies Unit

4 Technology Guidelines for School Coputer-based Technologies Local Area Network Manageent Security There are two fors of security: 1 Physical security (to avoid theft, fire, water and wilful physical daage); 2 Data security (to avoid loss / corruption of data and applications and to aintain privacy). 1 Physical Security It is iportant to store vital network coponents such as servers, hubs and routers in secure locations such as a strongroo. Most of this equipent needs little or no adinistration and should be safely stored to avoid theft or daage fro fire. Coponents such as cabling should be concealed in conduit wherever possible and should not be easily visible when run outside buildings. Siilarly, coponents such as ain power switchboards should always be kept locked. 2 Data Security If data security has not been investigated thoroughly before configuring the syste, difficulties and frustrations ay arise. A syste could be developed so it is easy to break into through a very lax security fraework, allowing students to access parts of the syste and cause data daage. On the other hand, it could be too difficult to navigate because of the overuse of passwords and tight restrictions. Effective data security involves the allocation of trustee rights to users or groups of users for specific parts of each server and the allocation of passwords where appropriate. Networkaware enu systes that restrict access to sensitive areas of the syste (such as MS-DOS), providing Read-Only access to application areas on the servers and the protection and regular changing of sensitive passwords can ensure effective and secure use of your network syste. As a general rule, only allocate each user the iniu rights necessary. Data Storage and Manageent The issue of data storage can be coplex. In a networked situation, it is usually best to store all iportant data files on a fileserver rather than on floppy diskettes or on local hard disks in workstations or standalones. The reason for this is that the school s contingency plan should include total and regular backup of all fileservers while there ay not be any direction to Inforation Technology Bureau MLANS304.doc 4 Educational Technologies Unit

5 Technology Guidelines for School Coputer-based Technologies Local Area Network Manageent backup local workstations. Losing docuents or other data files through corruption or accidental deletion when there are no backups will require the anual recreation of those files. This is both tie-consuing and avoidable. If it is decided that all iportant data storage is to be on the fileserver(s), then it is iportant to ensure adequate disk space is available to allow this to occur. A tape backup solution ust also be provided which is capable of duplicating this aount of data storage. Tape backups should be stored in a secure area, preferably away fro the fileserver. Backup tapes could be destroyed or stolen if stored together with the server. When setting up data storage areas on a file server, it should be noted that staff ay require separate areas of the disk where they have private use and shared use. A user s private folder should not be visible to other users while the shared folder should be visible to all users. Separate shared folders can be created for staff and students. If it is decided that no data is to be stored on the server(s) and all files are to be saved at the local workstation or on floppy diskette, then it is vital that individual users be aware of their own responsibility to ake their own backups of any data files they create. Regardless of the ethod of data storage chosen, it is up to the user to periodically reove unwanted, old or outdated data files fro the syste to free up valuable disk space. The Network Adinistrator should regularly check available disk space to ensure sufficient capacity is available at all ties. Backup Strategies Regular backups of data on servers iniises the risk of data loss and daage caused by disk failures, virus infection or network probles. Backup procedures should be carefully planned and adhered to. Coercial backup progras such as Backup Exec are available to facilitate the procedures required for effectively anaging this aspect of data security. These are best used in conjunction with tape-drive hardware, which uses edia capable of storing high volues of data. Data drives and tapes are available in different capacities depending on requireents. Typically, a tape drive capable of backing up the contents of the server hard disk(s) to one tape is ideal. Inforation Technology Bureau MLANS304.doc 5 Educational Technologies Unit

6 Technology Guidelines for School Coputer-based Technologies Local Area Network Manageent The basic types of backup procedures are: Full backup, in which all selected files are copied onto a tape. Increental, in which backup occurs only for files which have been changed or created since the last full or increental backup. In developing a backup plan, consider the following: Storage of data tapes should occur in a secure environent such as the school safe where fire, water and theft risks are iniised. Periodically verify data tape reliability in recovering files. A full backup should preferably fit on one data tape cartridge. Label tapes with date, tie and type of backup (Full or Increental) Rotate the backup edia. Conduct a full backup each week, an increental backup daily and archive full backup tapes on a onthly basis. Server access to the tape backup syste should be on an authorised, password protected basis only. Upgrading Existing Software and Installing New Software Installing software on file servers is very different to installing software on standalone coputers. For this reason it is iportant to obtain specialist advice if the school s Network Adinistrator is not failiar with the various odels of networked software installation. Because a server-based network is a centralised coputer syste, the entire concept of its use is to generate and follow standards and standardisation. It is recoended that decisions be ade on which specific products are to be chosen for each category of coputer use. For exaple, for the task of general word processing, the school could standardise on either Microsoft Word or Word Perfect but not both. Perhaps an integrated product such as Claris Works or Microsoft Works could cover several categories of coputer use. The reason for choosing one product in each category is to standardise file forats for ease of data transfer and to strealine staff training requireents. The selection of specific software for networked use across the school should always be ade by the school s technology coittee. Inforation Technology Bureau MLANS304.doc 6 Educational Technologies Unit

7 Technology Guidelines for School Coputer-based Technologies Local Area Network Manageent The processes of upgrading to new versions of existing software and installation of new software involves not only how to ake the new software available to users, but how to ensure the new software will be used efficiently. This ay involve foral training, in-service training or peer support. Whichever ethod of staff training is chosen, the goal should be to ensure the continued use and acceptance of technology throughout the change. Coputer Viruses Coputer viruses are a separate concern for network adinistrators. As these can potentially be devastating to a coputer network, it is iperative that easures be taken to avoid infection. The best way to avoid infection is the education of users. Understanding what a virus is and how it spreads, and adopting work practices aong users to ensure infection cannot occur is the first step. Virus protection software is the safety net in case a virus anages to get through good work practices. What is a Coputer Virus? All viruses are coputer progras written by a person or persons - they are not biological. To be classed a virus, the progra ust have the ability to replicate and igrate fro coputer to coputer. This can be either via diskette or across a network. As well as propagating, viruses inherently cause daage. There are other rogue progras to be aware of such as Logic Bobs, Trojan Horses and Wors which are not viruses, but can be equally daaging. How Does a Virus Spread? All viruses hide soewhere on a floppy disk or a hard disk. Most viruses fall into the following categories: Boot Sector / Partition Table Viruses These live in the boot areas of disks and load into eory whenever the coputer is booted. They infect each diskette placed in the drive. Executable File Viruses These attach theselves to executable files (progras) and function whenever the infected progra is loaded. They infect other uninfected progras when they are loaded. Inforation Technology Bureau MLANS304.doc 7 Educational Technologies Unit

8 Technology Guidelines for School Coputer-based Technologies Local Area Network Manageent Multi-Partite Viruses These viruses are ade up of separate coponents and can be alost undetectable whilst at the sae tie infecting every file on your coputer. Macro Viruses These are ebedded in acros defined within certain word processing docuents or spreadsheet files. They are transferred by the sharing of the infected docuents. Soe Effects of Viruses The daage that a virus can cause is liited only by the iagination of its author. Soe of the typical effects include: degradation of processing speed; inappropriate screen essages; corruption of printouts; file deletion; corruption of files and File Allocation Tables (FAT); low-level foratting of disks. File allocation Tables: a record keeping structure DOS uses to keep track of the location of every file on the disk i.e. like an index. How to Avoid Viruses Viruses are getting sarter everyday, becoing harder to detect and there are thousands of different viruses in circulation. It is alost ipossible to totally avoid viruses however, these suggestions should help. 1 Ensure that coplete and regular backups are aintained for all coputer systes; 2 Use an up-to-date virus scanning progra on both file servers and workstations; 3 Be wary of all disks that have coe fro external sources (even fro hoe); 4 Do NOT participate in copyright infringeent; 5 Write-protect all original progra diskettes before using the; and 6 Install virus scanning software that autoatically scans for viruses. What if a Virus is Found? If the steps above were followed, this shouldn t happen, but if it does, follow the steps below: 1 Switch off the coputer and place a sign to let others know the coputer is infected; Inforation Technology Bureau MLANS304.doc 8 Educational Technologies Unit

9 Technology Guidelines for School Coputer-based Technologies Local Area Network Manageent 2 Isolate all diskettes associated with that coputer. It is likely that soe or all are infected as well; 3 Attept to find the possible source of the virus; 4 Ask for help if unsure of how to reove the virus; and 5 Reinforce the steps listed above to avoid future viruses. Reoving a Virus The reoval of coputer viruses fro both standalone coputers and fro network file servers can be a coplex, tie-consuing procedure. Further inforation and evaluation copies of virus reoval progras is available fro the following Website: Inforation Technology Bureau MLANS304.doc 9 Educational Technologies Unit